Method for making recessed filters, filter rods, or the like



B. SCHUBERT 3,052,163

OR THE LIKE 2 Sheets-Sheet 1 Sept. 4, 1962 METHOD FOR MAKING RECESSED FILTERS, FILTER RODS,

Filed July 1, 1959 P 4, 1962 B. SCHUBERT 3,052,163

D FOR MAKING RECESSED FILTERS, FILTER RODS, OR THE LIKE 2 Sheets-Sheet 2 METHO Filed July 1, 1959 United tates Bergedorf, Germany Filed July 1, 1959, Ser. No. 824,288 Claims priority, application Germany July 4, 1958 4 Claims. (Cl. 931) In the manufacture of filter tip cigarettes in which the cigarettes are provided at one end with filter bodies or recessed filter bodies, it is customary to surround the filter bodies or filter rods with a wrapping band of relatively thick or hard material. In particular, when the cigarettes are provided with a recessed filter, it is required that the recess or hollow space formed at the end of the filter tip cigarette is provided with a sleeve having a sufficient rigidity. When these wrapping bands or sleeves are formed from a suitable length of material which is shaped into the form of a tube or sleeve, it was discovered that in view of the hardness of the material it is ditficult to connect the ends of the band in a satisfactory manner, because it is difficult to bend the end portions in a sufficient manner so that the edges properly abut or are caused to overlap properly to form a cylindrical tube. In particular, when the ends of these hard strips are overlapped, there is formed at the overlapped portion a certain inaccuracy which prevents a good adherence of the overlapped portions. I

It is an object of the invention to preform the wrapping band at its ends which are to abut or which are to overlap when the sleeve is formed by providing these ends with a preformed curvature on the same side, preferably having a radius of smaller size than the final radius of the sleeve to be formed.

It is also an object of the invention to produce this preformed curvature by providing a continuous strip of material, from which the individual wrapping bands are cut in the range Where this strip is to be cut, with a deformation. This deformation is effected in such a manner that a crimp is produced in the continuous strip. This crimp is directed approximately concentric or approximately parallel to the curvature of the completed filter. The crimping of the continuous strip is made with a radius which is smaller than the radius of the tubular wrapping to be produced later from this wrapping strip.

After the continuous strip has been provided at the proper places with a crimp, the strip is continuously advanced toward a cutting device which severs the continuous strip into individual pieces at the places where the crimps were produced. By the time, however, the continuous strip reaches the cutting device the previously formed crimps in the continuous strip have flattened out again, but nevertheless the material has been relieved of its tension at these points and when later the tubular wrapping is formed, the ends of the wrapping band will readily adapt themselves to the desired cylindrical form.

The device for performing the method consists principally of a crimping device, for instance of two cooperating rollers, one of which is provided with wedge-shaped projections while the other roller is provided with corresponding recesses in its circumference. This crimping device may be arranged by way of example, between a pair of positively driven feed rollers and an adhesive applying device which provides the continuous strip on one side with an adhesive before the continuous strip is cut into individual wrapping bands by another device.

The drawing illustrates by way of example a device for practicing the invention and also several embodiments of filter bodies provided with a wrapping in accordance with the prior art and also in accordance with the invention.

FIG. 1 illustrates diagrammatically a side elevation view of the device for preparing a continuous wrapping strip for cutting into individual bands for wrapping the same around a filter body or the like.

FIG. 2 illustrates in an enlarged view a cross section of the cooperating crimping rollers.

FIGS. 3 and 3a show each a sectional view of recessed filter bodies which were produced without employing the crimping device of the invention.

FIGS. 4 and 4a show each a cross sectional view of recessed filter bodies which were produced when employing the crimping device of the present invention, and

FIGS. 5 and 6 illustrate in views similarly to FIGS. 1 and 2 a device for preparing a wrapping band used for the filter rod method.

Referring to the drawing, FIG. 1 illustrates a device for feeding individual wrapping bands B to a machine for producing recessed filter rods in a so-called transverse method. The individual wrapping bands B are cut on a suction drum 4 from a continuous strip 3 which is fed toward the circumference of said suction drum 4.

A driven pair of rollers '1, 2 feed a continuous strip 3 of wrapping material toward an adhesive applying device L and then toward a suction drum 4 on which the strip 3 is cut by a cutting drum 5 into individual wrapping bands B. The speed of the feed rollers 1, 2 and the speed of the suction drum 4 is adjusted relatively to one another in such a manner that the individual wrapping bands B will be placed on the suction drum 4 in a circumferentially spaced manner. In accordance with the present invention a crimping device in the form of a pair of rollers 6 and 7 is arranged between the feed rollers I, 2 and the adhesive applying device L. One of the crimping rollers 7 is provided on its circumference with axially extending wedge-like ribs 7a and the other crimping roller 6 is provided with corresponding axially extending grooves 6a in its circumference.

The operation of the device is as follows: The continuous strip 3 is fed by the feed rollers 1, 2 toward the crimping rollers 6, 7 and is provided at the points where later the knives of the cutting roller 7 cut the strip 3 as at S with a crimp. This crimp according to FIG. 2 has the shape of a downwardly directed V following the shape of the groove 6a in the roller 6. During the continuous movement of the strip 3 toward the adhesive applying device L and the suction drum 4 the crimp disappears or is flattened out again but the tension of the material of the strip at the points where the crimps were produced has been substantially removed or at least sufficiently decreased so that later on when the individual bands B are formed into tubular shapes, the ends of the bands will be bent or curved without difiiculties and will conform correctly to the desired curvature of the filter tips.

In order to explain the invention more clearly, the FEGS. 3 and 3a illustrate cross sectional views of recessed filter rods or of solid filter rods as they are being produced 'by the heretofore employed devices. According to FIG.

3 the filter rod F1 is surrounded by a hard wrapping band BI the ends of which are in abutting engagement. In order to keep the ends of the strip B1 in abutting relationship there is also provided a thin paper strip P1 made of ordinary cigarette paper which is wrapped around the wrapping band B1 and at its ends is caused to overlap. It will be noted, however, that in view of the tension existing in the ends of the wrapping band B1 the ends of the latter are somewhat raised away from the filter body F1 as shown in FIG. 3 and it may happen that in view of this tension a deformation of the filter body F1 may occur.

FIG. 4 illustrates a cross section of a filter body made Great Britain specification No.

in accordance with the present invention. It will be noted that the ends of the hard wrapping band B3 are perfectly curved and follow the cylindrical shape of the filter body F3. As a result, a perfect abutment of the ends of the wrapping band B3 is produced and when now the cigarette paper strip P3 is wrapped around the filter F3 to cover the abutment line of the wrapping band B3, it will be noted that also the paper band P3 the ends of which are overlapped follow very closely the cylindrical shape of the wrapping band B3.

FIG. 3a shows another well known type of a cross section of a recessed filter rod or of a solid filter rod in which the hard wrapping band B2 is overlapped at its ends. Since the two end portions of the wrapping band B2 have a different curvature and since in particular the curvature of the lower portion of the wrapping band is less than the upper end portion, it is obvious that a connection or an adherence of the overlapped end portions will not take place over the entire area of the overlap, and it is the experience that such Wrapping bands for filter bodies do open up very readily after the wrapping band has been placed around the filter body.

FIG. 4a shows now in what manner the present invention provides a substantial improvement, because the curvatures of both end portions of the hard wrapping band B4 are alike in the entire overlapped area, because in view of the prior crimping which took place at the ends of the bands and there will be no tension at these ends and, therefore, the end portions follow accurately the shape of the filter rod F4.

The above described method of the invention has been described in connection with the production of recess filters or solid filters in a so-called transverse method in which the filter bodies are moved transversely to their longitudinal direction While the wrapping takes place. It is, however, also possible to employ the invention, namely the crimping of the wrapping band, when the filter bodies or filter rods are produced in the so-called rod method." In the last method the filter bodies are moved lengthwise to their longitudinal axis and it is of course required that the ribs 7a and the grooves da are not arranged in axial direction on the rollers 6 and 7 as shown in FIG. 2, but they have to extend in a ring shaped manner or in a concentrical manner respectively around these rollers.

Referring to FIGS. 5 and 6 which illustrate such a rod method, the rollers 1, 2 feed the strip 3 over an adhesive applying device L and a reversing roller 1% to a rod forming machine (not shown). Between the feed rollers 1, 2 and the adhesive applying device L are arranged the cooperating preforniing rollers 106, 107 of which the roller 106 has wall portions ltloa rounded at the ends of its circumference and engages correspondingly shaped wall portions 107a of the other roller 107 (FIG. 6). The strip 3 passes through these preforming rollers 106, 1%! and in view of the rounded portions 106a and lfila is provided at its marginal portions with curvatures. These curvatures straighten out again between the rollers 1%, Hi7 and the reversing roller 194, but the tension of the material at these marginal portions of the strip is removed or reducedso that these marginal portions during the forming of the tubular sleeve will have the deslred curvature and will form a near perfect cylindrical sleeve and a smooth joint where the marginal portions abut or overlap. The rod method is described in detail in our What I claim is:

1. A method of manufacturing recessed filter bodies, solid filter bodies, and the like, for filter tip cigarettes, including the steps of feeding a continuous strip of relatively stiff and diflicult to roll wrapping material, forming transverse crimps at predetermined spaced apart points for releasing the tension from those areas of the fed strip which after the crimping step form the seam of the Wrapping, stretching said strip which has been partly released from tension, applying adhesive to said strip, transversely cutting said strip Whose tension has been partly released at the centers of said crimp-s, and finally wrapping the individual bands formed from the partly tension released strip around filter bodies in such a manner that the released ends of said bands formed by previously crimped portions of said continuous strip are directed toward said filter bodies and form a smooth continuous connection when wrapped around said filter bodies which is substantially concentric to the curvature of said filter bodies, said predetermined spaced points being spaced apart a distance equal to the circumference of said filter bodies.

2. A method of manufacturing recessed filter bodies, solid filter bodies, and the like, for filter tip cigarettes, including the steps of feeding a continuous strip of relatively s'tiif and difiicult to roll wrapping material, forming transverse crimps at predetermined spaced apart points for releasing the tension from those areas of the fed strip which after the crimping step form the seam of the wrapping, said crimps being formed so as to project all from one side of said strip and to have a radius of curvature which is smaller than the radius of curvature of the filter bodies to be provided with a wrapper formed from said strip, stretching said strip which has been partly released from tension, applying adhesive to said strip, transversely cutting said strip whose tension has been partly released at the centers of said crimps, and finally wrapping the individual bands formed from the partly tension released strip around filter bodies in such a manner that the released ends of said bands formed by previously crimped portions of said continuous strip are directed toward said filter bodies and form a smooth continuous connection when wrapped around said filter bodies which is substantially concentric to the curvature of said filter bodies, said predetermined spaced points being spaced apart a distance equal to the circumference of said filter bodies.

3. A method of manufacturing recessed filter bodies, solid filter bodies, and the like, for filter tip cigarettes, including the steps of feeding a continuous strip of relatively stiff and difficult to roll wrapping material, forming transverse crimps at predetermined spaced apart points for releasing the tension from those areas of the fed strip which after the crimping step form the seam of the Wrapping, stretching said strip which has been partly released from tension, applying adhesive to said strip, said applied layer of adhesive being directed to one side of said previously crimped and straightened strip, transversely cutting said strip whose tension has been partly released at the centers of said crimps, and finally wrapping the individual bands formed from the partly tension released strip around filter bodies in such a manner that the released ends of said bands formed by previously crimped portions of said continuous strip are directed toward said filter bodies and form a smooth continuous connection when Wrapped around said filter bodies which is substantially concentric to the curvature of said filter bodies, said predetermined spaced points being spaced apart a distance equal to the circumference of said filter bodies.

4. A method of manufacturing recessed filter bodies, solid filter bodies, and the like, for filter tip cigarettes, including the steps of feeding a continuous strip of relatively stiff and diflicult to roll wrapping material, forming transverse crimps at predetermined spaced apart points for releasing the tension from those areas of the fed strip which after the crimping step form the seam of the wrapping, stretching said strip which has been partly released from tension, applying adhesive to said strip, transversely cutting said strip whose tension has been partly released at the centers of said crimps, and finally Wrapping the individual bands formed from the partly tension released strip around filter bodies in such a manner that the released ends of said bands formed by previously crimped portions of said continuous strip are directed toward said filter bodies and form a smooth continuous connection References Cited in the file of this patent UNITED STATES PATENTS Koerner May 13, 1913 Baldwin Jan. 16, 1917 6 Ruau Jan. 31, 1939 Merrill Mar. 26, 1957 Edwards Oct. 15, 1957 Schur Apr. 21, 1959 Korber et a1 Sept. 1, 1959 FOREIGN PATENTS France Nov. 26, 1956 

